Social interactions and environment are increasingly recognized as potentially important influences on reproductive function, health, and well-being. Although data are not available for reproductive maturation in boys, social factors influence time of menarche in girls. Depending on circumstances, early puberty may be either an asset or detriment to the social and physical development of the individual or to its lifetime survival and reproduction. The proposed pilot research will provide a first investigation into the physiological mechanisms underlying inter-individual variability in the timing of puberty and the length of adolescence in a wild population of non-human primates and into some of the social impacts on these mechanisms. We shall investigate the extent to which a sub-set of behavioral and social factors is correlated with maturational measures and what the temporal relationship is between detectable physiological and behavioral differences. Our aim is to determine the extent to which dominance status and aggressive/submissive interactions among juveniles and the juveniles' social interactions with adults predict physiological patterns of puberty, maturation, and adult rank attainment in males and females. We hypothesize that this relationship is mediated via the hypothalamic- pituitary-gonadal (HPG) and HP-adrenal (HPA) axes. Social environment will be characterized by dominance rank and by variability in the specific behaviors that determine rank, such as, spatial displacements, aggression, and submission. We will measure fecal hormone concentrations of estrogens, testosterone, and glucocorticoids and correlate these with behaviors exhibited during the transition between juvenescence to adolescence and adolescence to adulthood in males and females.